Browser displaying Uncaught Exception

[badrifx]

I changed my AsyncCallback from List<String> to Map<String, String>.

void findCookieByName(String cookieName1, String cookieName2, AsyncCallback<Map<String, String>> asyncCallback);

I checked entire code. I am using Map everywhere.

After deploying the app & running the app, I see following error in browser.

2013-05-14 18:28:43,922 [ERROR] Uncaught Exception
java.lang.ClassCastException:
null
at Unknown.Wtb(Unknown source:0)
at Unknown.qS(Unknown source:0)
at Unknown.sp(Unknown source:0)
at Unknown.C6(Unknown source:0)
at Unknown._N(Unknown source:0)
at Unknown.DO(Unknown source:0)
at Unknown.anonymous(Unknown source:0)
at Unknown.JH(Unknown source:0)
at Unknown.anonymous(Unknown source:0)

Is there a way to obtain a proper stack trace which will indicate where is it failing exactly?

Browser has this log:

013-05-14 18:37:17,340 [gwt-log]
gwt-log-2.6.2 - Runtime logging for your Google Web Toolkit projects
Copyright 2007-2008 Fred Sauer
The original software is available from:
http://allen-sauer.com/gwt/

Thanks